Image forming apparatus

Abstract

To solve the problem in which: in recent years, use of wireless communication is increased, and an improvement in convenience in wireless communication is demanded.SOLUTION: When an image forming apparatus operates as a master station that determines a communication channel used in wireless communication S1007, the image forming apparatus transmits a second trigger frame conforming to the IEEE802.11 standard including information indicating that carrier sense is not executed, to a slave station connected to the master station S1008.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to an image forming apparatus.

Background Art

[0002] Patent Document 1 discloses a technology that allows an image forming apparatus to execute wireless communication in infrastructure mode and wireless communication in ad-hoc mode in parallel via an access point.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, wireless communication has been used in various scenarios, and there is a demand for providing highly convenient wireless communication.

Means for Solving the Problems

[0005] To solve the above problems, an image forming apparatus is provided, comprising: a receiving means for receiving information about an external access point from a terminal device via a direct connection established with the terminal device without going through an external access point outside the image forming apparatus when the wireless setting mode is enabled; a first mode for performing wireless communication via an external access point outside the image forming apparatus; and a second mode for performing wireless communication without going through an external access point outside the image forming apparatus; and a second mode compliant with the IEEE 802.11 standard, which includes information about performing carrier sense from the connected external access point based on the information about the external access point received by the receiving means. The system is characterized by comprising: receiving means for receiving a trigger frame; first transmitting means for performing carrier sensing and then transmitting data if the first trigger frame contains information indicating that carrier sensing should be performed; second transmitting means for transmitting a second trigger frame compliant with the IEEE 802.11 standard to a slave station connected to the master station, which contains information indicating that carrier sensing should not be performed when the image forming apparatus is operating as a master station for determining the communication channel used in the second mode wireless communication while the first and second modes are enabled; and printing processing means for performing printing processing on paper based on print data received from the slave station. [Effects of the Invention]

[0006] According to the present invention, it becomes possible to provide more efficient wireless communication technology. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows an example of the system configuration in this embodiment. [Figure 2] (A) A diagram showing an example of the hardware configuration of a mobile terminal. (B) A diagram showing an example of the hardware configuration of an image forming apparatus. [Figure 3] This figure shows an example of the functional configuration of an access point. [Figure 4] This figure shows an example of communication processing in this embodiment. [Figure 5] This figure shows an example of a frame configuration. [Figure 6] This figure shows an example of a frame configuration. [Figure 7] This figure shows an example of a frame configuration. [Figure 8] This figure shows an example of communication processing in this embodiment. [Figure 9] This figure shows an example of the wireless setup process in this embodiment. [Figure 10] This diagram shows a flowchart executed in an image forming apparatus. [Modes for carrying out the invention]

[0008] The embodiments of the present invention will be described in detail below with reference to the drawings. It should be noted that these embodiments are merely examples, and unless otherwise specified, the specific examples of components, processing steps, display screens, etc., are not intended to limit the scope of the present invention.

[0009] (System Configuration) Figure 1 shows an example of the system configuration according to this embodiment. In one example, this system is a wireless communication system in which multiple communication devices can communicate with each other wirelessly. In the example in Figure 1, the system includes an access point 131, an MFP 151, and a mobile terminal 101. Note that the mobile terminal 101 is just one example and can be a notebook computer or a smartphone.

[0010] The MFP151 has printing, scanning, and faxing functions. Furthermore, the MFP151 in this embodiment has a communication function that allows it to communicate wirelessly with the 101. While this embodiment describes the use of the MFP151 as an example, it is not limited to this. For example, a facsimile machine, scanner, projector, or single-function printer may be used instead of the MFP151. MFP is an abbreviation for Multi-Function Peripheral. In this embodiment, a device equipped with printing functionality may also be referred to as an image forming apparatus.

[0011] Access point 131 is located separately (externally) from the mobile terminal 101 and MFP 151, and operates as a base station device for wireless LAN (WLAN). Access point 131 may also be referred to as external access point 131 or external wireless base station (or external master station). MFP 151, which has WLAN communication capabilities, can communicate in WLAN infrastructure mode via access point 131. In the following, access point may be referred to as "AP". Infrastructure mode may also be referred to as "wireless infrastructure mode" or "infrastructure mode".

[0012] Infrastructure mode is a mode in which the MFP151 communicates with other devices via external devices that form a network (e.g., access point 131). The connection with an external access point established by the MFP151 operating in infrastructure mode is called an infrastructure connection (hereinafter referred to as an infrastructure connection). In this embodiment, in an infrastructure connection, the MFP151 operates as a slave station, and the external access point operates as a master station. In this embodiment, a master station is a device that determines the communication channel used in the network to which the master station belongs, and a slave station is a device that does not determine the communication channel used in the network to which the slave station belongs, but uses the communication channel determined by the master station.

[0013] Access point 131 communicates wirelessly with communication devices that it has authorized to connect to its device (authenticated) and relays wireless communication between those communication devices and other communication devices. In addition, access point 131 may be connected to a wired communication network, for example, and can relay communication between communication devices connected to that wired communication network and other communication devices that are wirelessly connected to access point 131.

[0014] The mobile terminal 101 and the MFP 151 can use their respective WLAN communication functions to perform wireless communication in wireless infrastructure mode via the external access point 131, or in peer-to-peer mode without the external access point 131. Hereafter, peer-to-peer communication will be referred to as "P2P". Alternatively, communication without the external access point 131 may be referred to as direct wireless communication. P2P mode includes Wi-Fi Direct® and soft AP mode, etc. Hereafter, Wi-Fi Direct® may be referred to as WFD. P2P mode can also be described as communication compliant with the IEEE 802.11 series.

[0015] The P2P mode is a mode in which the MFP 151 communicates directly with another device such as the mobile terminal 101 without going through an external device that forms a network. In the present embodiment, the P2P mode includes an AP mode in which the MFP 151 operates as an access point. The connection information (SSID and password) of the access point that is enabled in the MFP 151 during the AP mode can be arbitrarily set by the user. Note that the P2P mode may include, for example, a WFD mode for the MFP 151 to perform communication via Wi-Fi Direct (WFD). Note that which one of a plurality of WFD-compatible devices operates as a parent station is determined, for example, according to a sequence called Group Owner Negotiation. Note that the parent station may be determined without executing the Group Owner Negotiation. A device that is a WFD-compatible device and serves the role of a parent station is particularly referred to as a Group Owner. A direct connection with another device established by the MFP 151 operating in the P2P mode is referred to as a direct connection. In the present embodiment, in the direct connection, the MFP 151 operates as a parent station, and another device (such as the mobile terminal 101) operates as a child station.

[0016] Next, the configurations of the mobile terminal of the present embodiment and a communication apparatus capable of communicating with the mobile terminal of the present embodiment will be described with reference to Figure 2. Further, although the following configuration is described as an example in the present embodiment, the present embodiment is applicable to any device capable of communicating with a communication apparatus, and the functions are not particularly limited to those shown in this figure.

[0017] The mobile terminal 101 includes an input interface 102, a CPU 103, a ROM 104, a RAM 105, an external storage device 106, an output interface 107, a display unit 108, a keyboard 109, a communication unit 110, a short-range wireless communication unit 111, a network interface 112, a USB interface 113, and the like. The CPU 103, the ROM 104, the RAM 105, and the like form a computer of the mobile terminal 101.

[0018] The input interface 102 is an interface for accepting data inputs and operation instructions from a user when an operation unit such as a keyboard 109 is operated. The operation unit may be a physical keyboard, physical buttons or the like, or may be a soft keyboard, soft buttons or the like displayed on the display unit 108. That is, the input interface 102 may accept inputs (operations) from the user via the display unit 108.

[0019] The CPU 103 is a system control unit that controls the entire mobile terminal 101. The ROM 104 stores fixed data such as control programs executed by the CPU 103, data tables, and embedded operating system (hereinafter referred to as OS) programs. In the present embodiment, each control program stored in the ROM 104 performs software execution control such as scheduling, task switching, and interrupt processing under the management of the embedded OS stored in the ROM 104.

[0020] The RAM 105 is configured of an SRAM (Static Random Access Memory) or the like that requires a backup power supply. Since data in the RAM 105 is retained by a primary battery for data backup (not illustrated), important data such as program control variables can be stored without being lost. In addition, a memory area for storing setting information of the mobile terminal 101, management data of the mobile terminal 101, and the like is also provided in the RAM 105. The RAM 105 is also used as the main memory and work memory of the CPU 103.

[0021] The external storage device 106 stores, for example, a print information generation program for generating print information interpretable by the printing apparatus 115. The output interface 107 is an interface that performs control for causing the display unit 108 to display data and notify the state of the mobile terminal 101.

[0022] The display unit 108 consists of LEDs (light-emitting diodes) and LCDs (liquid crystal displays) and displays data and notifies the status of the mobile terminal 101. The communication unit 110 is configured to connect to devices such as the MFP 151 and access point (AP) 131 to perform data communication. For example, the communication unit 110 can connect to an access point (not shown) inside the MFP 151. By connecting the communication unit 110 and the access point inside the MFP 151, the mobile terminal 101 and the MFP 151 can communicate via P2P. The communication unit 110 may communicate directly with the MFP 151 via wireless communication, or it may communicate via an AP 131 unit located outside the mobile terminal 101 and the MFP 151. External devices include external access points (such as access point 131) located outside the mobile terminal 101 and the MFP 151, as well as devices other than access points that can relay communication. In this embodiment, the wireless communication method used by the communication unit 110 is Wi-Fi (WirelessFidelity) (registered trademark), a communication standard compliant with the IEEE 802.11 series. The access point 131 may be, for example, a wireless LAN router or similar device.

[0023] The short-range wireless communication unit 111 is configured to wirelessly connect to devices such as the MFP 151 at short range and perform data communication, and communicates using a different communication method than the communication unit 110. The short-range wireless communication unit 111 can connect to, for example, the short-range wireless communication unit 157 in the MFP 151. Examples of communication methods include Near Field Communication (NFC), Bluetooth® Classic, Bluetooth Low Energy (BLE), and Wi-Fi Aware.

[0024] The network interface 112 is a connection interface that controls communication via wireless and communication processing via wired LAN cables.

[0025] The USB interface 113 is a connection interface that controls USB connections via a USB cable. Specifically, the USB interface 113 is an interface for connecting to devices such as the MFP 151 and the external access point 131 via USB and performing data communication.

[0026] Next, I will explain the MFP151. The MFP151 includes a ROM152, RAM153, CPU154, print engine155, communication unit156, short-range wireless communication unit157, input interface158, operation unit159, output interface160, display unit161, network interface162, USB interface163, etc. The ROM152, RAM153, CPU154, etc. form the computer of the MFP151.

[0027] The communication unit 156 controls the communication processing using each interface. For example, the MFP 151 can operate in infrastructure mode and P2P (Peer to Peer) mode as modes for performing communication using the communication unit 156.

[0028] Specifically, the communication unit 156 can operate as an access point within the MFP 151. For example, the MFP 151 will operate as an access point if the user instructs it to activate the internal access point. In this embodiment, the wireless communication method used by the communication unit 156 is a communication standard compliant with the IEEE 802.11 series. In the following description, Wi-Fi (WirelessFidelity) (registered trademark) (Wi-Fi communication) refers to a communication standard compliant with the IEEE 802.11 series. The communication unit 156 may have hardware that functions as an access point, or it may operate as an access point through software that enables it to function as an access point. When the communication unit 156 operates as a master station, it can maintain parallel P2P wireless connections with a predetermined number of slave station devices (e.g., 3 or fewer). The communication unit 156 can perform wireless communication using frequency bands selected from 2.4GHz, 5GHz, and 6GHz.

[0029] The short-range wireless communication unit 157 is configured to establish a short-range wireless connection with a device such as a mobile terminal 101, and can, for example, connect to the short-range wireless communication unit 111 within the mobile terminal 101. Examples of communication methods include NFC, Bluetooth Classic, BLE, and Wi-Fi Aware.

[0030] RAM153 consists of SRAM and other components that require a backup power supply. Since RAM153's data is held by a primary battery (not shown) for data backup, important data such as program control variables can be stored without being lost. RAM153 also includes a memory area for storing MFP151 configuration information and management data. Furthermore, RAM153 is used as the main memory and work memory for the CPU154, storing a receive buffer for temporarily saving print information received from mobile terminals such as the 101, and various other information.

[0031] ROM152 stores fixed data such as control programs, data tables, and OS programs executed by the CPU154. In this embodiment, each control program stored in ROM152 performs software execution control such as scheduling, task switching, and interrupt handling under the management of the embedded OS also stored in ROM152.

[0032] The CPU 154 is the system control unit and controls the entire MFP 151.

[0033] The print engine 155 performs a printing process to form an image on a recording medium by adding a recording material such as ink to paper, based on information stored in the RAM 153 or print jobs received from a mobile terminal 101, and outputs the print result. Generally, the amount of data for print jobs transmitted from a mobile terminal 101 is large, so it is necessary to use a communication method that enables high-speed communication for the communication of print jobs. For this reason, the MFP 151 receives print jobs via a communication unit 156 that enables communication at a higher speed than the short-range wireless communication unit 157. Note that printing using ink is just one example, and printing may also be performed using an electrophotographic method with toner. Furthermore, the MFP may be a cartridge type that uses cartridges, or an MFP that refills ink from an ink bottle into its ink tank.

[0034] Furthermore, the MFP151 may be equipped with optional memory devices such as an external HDD or SD card, and the information stored in the MFP151 may be stored in such memory.

[0035] The input interface 158 is an interface for receiving data input and operation instructions from the user when an operation unit 159, such as a physical button, is operated. The operation unit may also be a soft keyboard or soft buttons displayed on the display unit 161. In other words, the input interface 158 may also receive input from the user via the display unit 161.

[0036] The output interface 160 is an interface that controls the display unit 161 to display data and notify the status of the MFP 151.

[0037] The display unit 161 consists of LEDs (light-emitting diodes) and LCDs (liquid crystal displays), and is used to display data and notify the status of the MFP 151.

[0038] The USB interface 163 is an interface that controls USB connections via a USB cable. Specifically, the USB interface 163 is an interface for connecting to devices such as the MFP151 or external access points via USB and performing data communication.

[0039] Figure 3 is a block diagram showing an example of the functional configuration of AP131. AP131 has, for example, a wireless LAN control unit 301, a trigger frame control unit 302, a received frame analysis unit 303, a UI control unit 304, a storage unit 305, and a bandwidth distribution unit 306.

[0040] The wireless LAN control unit 301 performs control for sending and receiving wireless signals with other wireless LAN communication devices. The wireless LAN control unit 301 can be implemented, for example, by a program for controlling the baseband circuit, RF circuit and antenna for the wireless LAN. The wireless LAN control unit 301 performs wireless LAN communication control in accordance with the IEEE 802.11 standard series and performs wireless communication with STAs that comply with the IEEE 802.11 standard series.

[0041] The Trigger frame control unit 302 controls the transmission of a Trigger frame to an STA that has successfully authenticated, via the Wireless LAN control unit 301. When the STA receives a Trigger frame, it transmits an Uplink (UL) frame in response to that frame. When AP131 receives the UL frame via the Wireless LAN control unit 301, the Received Frame Analysis Unit 303 interprets the contents of the received UL frame. For example, if the received UL frame contains AC information, the Received Frame Analysis Unit 303 obtains the AC information through analysis and determines which AC data the STA that sent the UL frame has.

[0042] The bandwidth allocation unit 306 determines, based on the information acquired by the received frame analysis unit 303, the width of the frequency band to be allocated for data transmission to each STA, the center frequency of the frequency band, and the time for allocating the frequency band. In other words, the bandwidth allocation unit 306 determines, for each STA, which frequency range of radio resources to allocate and at what timing. The trigger frame control unit 302 notifies each STA of the allocation determined by the bandwidth allocation unit 306 via a trigger frame and causes it to transmit a UL frame according to that allocation.

[0043] The UI control unit 304 is implemented by a program that controls user interface hardware such as a touch panel or buttons for receiving operations on AP131 by a user (not shown) of AP131. The UI control unit 304 may also have functions for presenting information to the user, such as displaying images or outputting sound. The storage unit 305 is a storage function that may consist of ROM and RAM for storing programs and data on which AP131 operates.

[0044] In IEEE 802.11ax, the frequency band can be allocated in a size smaller than the conventional 20 MHz, allowing many terminals to use wireless resources simultaneously. This allocation of wireless resources is performed using OFDMA (Orthogonal Frequency Division Multiple Access). In IEEE 802.11ax, for example, a 20 MHz bandwidth is divided into nine blocks, each containing 26 subcarriers (tones) that do not overlap on the frequency axis, and wireless resources are allocated to terminals in block units. This allocation unit block is called a Resource Unit (RU), and the size of the RU can be determined according to the frequency bandwidth and the number of terminals receiving the wireless resource allocation. The size of the RU is expressed in units of the number of tones; for example, 26, 52, 106, 242, 484, 996, and 2 × 996 are available, but for a 20 MHz bandwidth, values ​​of 242 or less are available. When allocating the entire 20 MHz bandwidth to a single terminal, a maximum of 242 tones can be allocated. On the other hand, if, for example, nine terminals simultaneously use a 20MHz bandwidth, 26 tones will be allocated to those terminals. In this way, by dividing the frequency band into the smallest allocation unit of 26 tones, nine terminals can communicate simultaneously using a 20MHz bandwidth. Similarly, when frequency bands of 40MHz, 80MHz, and 160MHz are used, up to 18, 37, and 74 terminals can communicate simultaneously, respectively.

[0045] Next, we will explain the basic flow of multi-user (MU) communication in UL using Figure 4. First, AP131 sends a Buffer Status Report Request (BSR Request) via the Trigger frame control unit 302 (S401). An example of the structure of the frame sent at this time is shown in Figure 5. Figure 5 contains information from 501 to 508. In the following, fields that are not relevant to the explanation in this embodiment will be omitted. In this embodiment, AP131, MFP151, and mobile terminal 101 are capable of performing communication based on IEEE801.11ax.

[0046] Returning to Figure 4, each STA sends a Buffer Status Report (BSP) (S402). In S402, each STA notifies the AP whether or not there is data to send.

[0047] When AP131 receives a BSP from each STA, it sends a Trigger frame (S403) based on that information, prompting the transmission of UL data. The frame transmitted at this time also has the format shown in Figure 5, for example. In Figure 5, the Frame Control field 501 is a field that contains a value indicating, for example, that it is an IEEE802.11ax Trigger frame. Here, an example of the data structure of Common Info 505 in Figure 5 is shown in Figure 6. Figure 6 contains information from 601 to 609. The Trigger Type subfield 601 stores "0". The UL Length subfield 602 stores a value corresponding to the communication period common to all STAs, and this value indicates the amount of data that each STA can transmit. If the value of the Trigger Type subfield 601 is "0", User Info fields 506-1 to 506-K are added to the frame in Figure 5. Refer to Figure 7 for details on User Info fields 506-1 to 506-K. Figure 7 contains information from 701 to 709. The STA is identified by the AID subfield 701, and the RU and tone size to be assigned to that STA are determined by the index value indicated by the RU Allocation subfield 702. The tone size is a value that indicates the width of the frequency bandwidth that can be assigned to each STA.

[0048] The AP reserves a communication channel to send a trigger frame. The AP then divides the reserved communication channel into multiple resource units in the frequency domain and assigns each resource unit to a terminal.

[0049] Let's return to the explanation in Figure 6. 604 is CS (Carrier Sense) Required and has a length of 1 bit. CS604 stores information indicating whether or not carrier sense should be performed. Therefore, if CS604 contains information indicating whether or not carrier sense should be performed, the communication device that received the trigger frame will perform carrier sense. On the other hand, if CS604 contains information indicating whether or not carrier sense should be performed, the communication device that received the trigger frame will not perform carrier sense.

[0050] When each STA receives a Trigger frame, it transmits a UL Data frame within the data volume range determined by the UL Length subfield 512 of the Trigger frame (S404). If CS604 contains information indicating that carrier sense should be performed, the STA performs carrier sense before executing S404. When AP131 receives a PPDU from each STA, it transmits a Multi Block Ack (Multi BA) as an acknowledgment of receipt (S405).

[0051] Next, the operation of the MFP151 will be explained using Figure 8. It is assumed that both infrastructure mode and P2P mode are enabled on the MFP151 at the user's instruction. For example, both modes are enabled when the user enables infrastructure mode and WFD mode using the MFP151's control panel. Furthermore, the MFP151 operates as a master station (e.g., a WFD group owner) in P2P communication. Note that P2P communication other than WFD mode may also be performed. For example, soft AP mode may be executed.

[0052] Here, we assume that MFP151 receives a trigger frame from AP131 in S403. Note that if both infrastructure communication and P2P communication are enabled, MFP151 refers to the communication channel used for infrastructure communication. MFP151 may also configure the network as a master station to perform P2P communication on the same communication channel. Alternatively, if both infrastructure communication and P2P communication are enabled, MFP151 refers to the communication channel used for infrastructure communication. MFP151 may also configure the network as a master station to perform P2P communication on a communication channel different from the communication channel used for infrastructure communication. In other words, in Figure 8, MFP151 receives a trigger frame from external access point 131 in S403 while both infrastructure mode and P2P mode are enabled.

[0053] The MFP151, acting as the master station, transmits a Trigger frame (S801). Here, the MFP151 uses the Trigger frame described above (Figure 5) to divide one communication channel (e.g., 20MHz) into multiple resource units and assign each resource unit to an STA, including the mobile terminal 101. In other words, the RU Allocation 606 of the Trigger frame transmitted by the MFP151 contains information about the allocation of resource units. The number of slave station devices to which the MFP151 assigns resource units is the maximum number that can maintain a direct connection in parallel. For example, if the communication unit 156 can maintain a P2P wireless connection with a maximum of 3 slave station devices in parallel, the maximum number of slave station devices to which resource units are assigned is 3. In other words, the maximum number of devices to which resource units are assigned, as specified in the trigger frame of S801, is the same as the maximum number of slave stations that can be maintained in parallel in a direct connection. The mobile terminal 101 transmits data to the MFP151 in S802 (S802). Here, the mobile terminal 101 sends data using the resource unit allocated in the trigger frame. For example, the mobile terminal 101 sends a print job in S802. The mobile terminal 101 may also send a request to obtain the status of the MFP 151 or a request to obtain the remaining amount of consumables (ink, toner, or paper) in S802.

[0054] As mentioned above, Figure 8 illustrates the configuration in which the MFP151 connects to the AP131 via user instructions using the MFP151's control panel. In this method, the user selects an SSID displayed on the MFP151's control panel and enters the password corresponding to the selected SSID into the control panel. However, the infrastructure connection between the MFP151 and the AP131 may be established by other methods. These methods will be explained using Figure 9.

[0055] The MFP151 activates its setup mode (wireless configuration mode) based on user instructions on the control panel (S901). This S901 prompts the MFP151 to activate its internal AP (Access Point) (S902). Note that it is possible to activate the setup mode in S901 even if an infrastructure connection to the AP has already been established before S901. In that case, the infrastructure connection will be disconnected. Also, if the MFP151 is operating as a P2P communication master station (e.g., a WFD group owner) before S901, the MFP151 may stop operating as a P2P communication master station (e.g., a WFD group owner) based on the instructions in S901.

[0056] The setup application is launched upon receiving instructions from the user (S903). In this embodiment, the wireless configuration process for the MFP151 is described using a PC, but a mobile device such as a smartphone may also be used.

[0057] When the user operates the setup application and instructs it to perform the wireless configuration process, the setup application performs the direct connection process with the internal AP. For example, the setup application retains the internal AP's SSID and password from the time of installation. Therefore, when instructed to perform the wireless configuration process, the setup application retrieves the internal AP's SSID and password and uses this information to instruct the system to establish a direct connection between the PC and the MFP151.

[0058] This instruction establishes a direct connection between the PC and the MFP151's internal access point (S904).

[0059] Next, the setup application instructs the MFP151 to discover APs via the direct connection established in S904 (S905).

[0060] Upon receiving instructions from S905, the MFP151 searches for available access points and sends a list of SSIDs as a result of the search (S907). The setup application sends the selected SSID and password from the list of SSIDs received by S907 as AP information (S908). For example, the setup application displays a list of SSIDs received by S907 and accepts a selection from the user. Then, the setup application displays a password input screen corresponding to the selected SSID and sends the entered password and the selected SSID as AP information.

[0061] Alternatively, if the PC was connected to AP131 immediately before S904, and the SSID of AP131 is included in the list of SSIDs sent by S907, the setup application will automatically send the SSID and password of AP131 via S905. In other words, the PC sends the AP information without displaying a list of SSIDs and accepting selection from the user. On the other hand, if the PC was connected to AP131 immediately before S904, and the SSID of AP131 is not included in the list of SSIDs sent by S907, the setup application may display the list of SSIDs received by S907 and accept selection from the user.

[0062] When the MFP151 receives AP information transmitted via S908, it stops the internal AP and establishes an infrastructure connection using the AP information transmitted via S908.

[0063] After the process in Figure 9 is completed, the user can enable WFD mode using the MFP151's control panel, thereby enabling both infrastructure mode and WFD mode, and the process in Figure 8 described above may be executed. Note that, as described above, if the MFP151 stops operating as a P2P communication master station (e.g., a WFD group owner) based on S901, the MFP151 will resume operation as a P2P communication master station (e.g., a WFD group owner) based on the process in S910. In this case, the MFP151 may resume operation as a P2P communication master station on the same channel as the infrastructure connection established in S910, or it may resume operation as a P2P communication master station on a different channel.

[0064] Next, the processes performed by the MFP151 will be explained using the flowchart in Figure 10. In this embodiment, the flowchart is realized when the CPU 154 reads and executes the program related to the flowchart's processing from the ROM 152. Furthermore, the flowchart in Figure 10 is performed after the infrastructure connection has been established by the process in Figure 9, and then the user enables WFD mode using the MFP151's operation panel, resulting in both infrastructure mode and WFD mode being enabled.

[0065] The CPU 154 receives the trigger frame described above from AP 131 in S403 of Figure 4 (S1001) and checks whether carrier sensing is required (S1002). S1002 is performed by referring to the information of CS Required604 in Figure 6. If it is determined in S1002 that carrier sensing is not required, the CPU 154 transmits the data to be transmitted to the target device via AP 131 without performing carrier sensing (S1005).

[0066] On the other hand, if it is determined in S1002 that carrier sensing is necessary, the CPU 154 performs carrier sensing (S1003) and senses the energy (power) of the radio waves generated in the communication channel specified by the trigger frame. The CPU 154 then determines whether the sensed energy is above a threshold (S1004). If it is determined that the energy of the radio waves generated in the communication channel is above the threshold, the CPU 154 determines that it cannot transmit data to AP 131 and returns to S1003. If it is determined to be No in S1004, the CPU 154 may skip the processing in S1005 and proceed to S1006.

[0067] On the other hand, if the CPU 154 determines that the power generated in the communication channel is below a threshold, it determines that it can send data to the AP 131 and sends the data to be sent to the target device via the AP 131 (S1005). For example, scan data obtained when the MFP 151 reads a document, or status information of the MFP 151, are sent in S1005. The CPU 154 sends the data to be sent using the resource units allocated to the MFP 151 by RU Allocation 702.

[0068] Next, the CPU 154 determines whether or not to operate as the master station for direct communication (S1006). For example, if the user instructs the MFP 151 to enable WFD, and it is determined through negotiation (comparison of Intent values) with the WFD communication partner device that it will operate as the group owner, the CPU 154 determines Yes in S1006. Also, if the user instructs the MFP 151 to enable software AP mode, the CPU 154 determines Yes in S1006.

[0069] The CPU 154 operates the MFP 151 as the master station for direct communication (S1007). Next, the CPU 154 sends a trigger frame to the slave station connected to it (e.g., the mobile terminal 101) (S1008). At this time, the MFP 151 sets information indicating that carrier sensing is not required to the CS Required 604 in Figure 6 and sends the trigger frame shown in Figure 5. The CPU 154 also allocates resource units to be used by the device connected to the MFP 151 (e.g., the mobile terminal 101) using the RU Allocation 702. In this case, the mobile terminal 101 sends data to the MFP 151 using the allocated resource units. For example, the mobile terminal 101 sends print data to the MFP 151 using the allocated resource units.

[0070] Although Figure 10 shows a configuration in which S1001 to S1005 are executed followed by S1006 to S1008, the CPU 154 may execute the processes in the reverse order. That is, it may execute S1006 to S1008 first, and then S1001 to S1005. Furthermore, S1001 to S1005 and S1006 to S1008 may be executed in parallel.

[0071] Furthermore, if infrastructure communication is disabled and only direct communication is enabled, CPU 154 may execute only S1006 through S1008.

[0072] According to this embodiment, even when AP131 instructs MFP151 to perform carrier sensing, MFP151 instructs its connected slave stations to transmit data without carrier sensing. This allows slave stations, including the mobile terminal 101, to efficiently transmit print data, etc., and for example, users can shorten the time from instructing to print to receiving the printed document.

[0073] (Other embodiments) In the embodiment described above, when the MFP151 is instructed to enter setup mode, it is described as activating an internal AP and receiving AP information. However, other configurations are also possible. For example, when the MFP151 is instructed to enter setup mode, the MFP151 establishes a connection with a nearby PC or smartphone via Bluetooth. Subsequently, the above-described steps S904 to S908 may be executed via the Bluetooth connection. Alternatively, other communication methods are also acceptable, not limited to Bluetooth.

[0074] The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions. [Explanation of Symbols]

[0075] 151 MFP

Claims

1. An image forming apparatus, When wireless setting mode is enabled, the receiving means receives information about the external access point from the terminal device via a direct connection established with the terminal device without going through an external access point outside the image forming apparatus. A communication control means that enables both a first mode in which wireless communication is performed via an external access point outside the image forming apparatus, and a second mode in which wireless communication is performed without going through an external access point outside the image forming apparatus. A receiving means that receives a first trigger frame compliant with the IEEE 802.11 standard, which includes information about the execution of carrier sense, from a connected external access point based on information about the external access point received by the receiving means, If the first trigger frame contains information indicating that carrier sensing should be performed, a first transmission means performs carrier sensing and then transmits the data. A second transmitting means transmits to a slave station connected to the master station a second trigger frame compliant with the IEEE 802.11 standard, which contains information indicating that carrier sensing is not performed when the image forming apparatus is operating as a master station that determines the communication channel used in the wireless communication of the second mode while the first and second modes are activated. An image forming apparatus characterized by comprising printing processing means that performs printing on paper based on print data received from the aforementioned substation device.

2. The system further includes a reading means for acquiring scanned data by scanning the original document. The image forming apparatus according to claim 1, characterized in that the first transmission means performs the carrier sensing and, if it determines that the sensed energy is below a threshold, transmits the scan data using one or more resource units allocated to the image forming apparatus by the first trigger frame.

3. The image forming apparatus according to claim 1, characterized in that the second trigger frame includes information indicating that carrier sensing is not performed and information regarding the allocation of one or more resource units.

4. The image forming apparatus according to claim 1, characterized in that the maximum number of devices to which the resource unit specified in the second trigger frame is allocated is the same as the maximum number of slave station devices that can be maintained in parallel in the second mode of wireless communication.

5. The image forming apparatus according to claim 1, characterized in that the image forming apparatus operating as a master station maintains in parallel wireless connections in the second mode with a predetermined number or fewer slave station devices.

6. The image forming apparatus according to claim 1, characterized in that the first mode of wireless communication and the second mode of wireless communication are performed using the same communication channel.

7. The image forming apparatus according to claim 1, characterized in that the first mode of wireless communication and the second mode of wireless communication are performed using different communication channels.

8. The image forming apparatus according to claim 1, characterized in that it performs wireless communication using a frequency band selected from 2.4 GHz, 5 GHz, and 6 GHz.

9. The image forming apparatus according to any one of claims 1 to 8, characterized in that the receiving means receives a first trigger frame in accordance with IEEE 802.11ax, and the second transmitting means transmits a second trigger frame in accordance with IEEE 802.11ax.

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